%I #7 Jun 07 2021 14:34:17

%S 8,10,19,33,65,149,304,643,1343,2880,6038,12805,27015,57283,120917,

%T 255898,540904,1144495,2419416,5117330,10820901,22886110,48394996,

%U 102347752,216437366,457724270,967964774,2047035882,4328987213

%N Number of 4 X n 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

%C Row 4 of A302635.

%H R. H. Hardin, <a href="/A302637/b302637.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +a(n-2) +2*a(n-3) +8*a(n-4) -6*a(n-5) -6*a(n-6) -13*a(n-7) -22*a(n-8) +7*a(n-9) +11*a(n-10) +28*a(n-11) +28*a(n-12) +2*a(n-13) -9*a(n-14) -27*a(n-15) -17*a(n-16) -2*a(n-17) +4*a(n-18) +10*a(n-19) +4*a(n-20) -2*a(n-21) -a(n-22) for n > 23.

%e Some solutions for n=5

%e ..0..1..0..1..0. .0..1..0..0..1. .0..1..1..0..1. .0..0..1..1..0

%e ..0..1..0..1..1. .0..1..0..1..0. .1..0..1..0..0. .0..1..0..1..0

%e ..0..0..0..1..0. .0..1..0..1..0. .1..0..1..0..1. .0..1..0..1..0

%e ..0..1..0..1..0. .1..0..0..1..0. .1..0..1..0..1. .0..1..1..0..0

%Y Cf. A302635.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 10 2018